1. Field
The present invention relates generally to a locking device, and more particularly to a locking device which can secure a heat sink to a heat generating device.
2. Prior Art
It is widely acknowledged that heat is produced during operation of electronic devices such as central processing units (CPUs). The heat produced must be quickly removed to ensure the CPUs to work normally. Generally, a heat sink is provided to remove heat from the CPU. In order to keep the heat sink intimately contacting with the CPU, a locking device is generally required.
Nowadays, numerous locking devices are used for securing heat sinks to electronic devices. Typically, a locking device comprising a rectangular retention module and a piece of elongated clip is often used. The retention module is located around a CPU on a printed circuit board. A heat sink is brought to rest on the retention module and the CPU. The clip comprises a central pressing portion and a pair of engaging portions extending perpendicularly from the pressing portion. The retention module has corresponding engaging members thereof for engaging with the engaging portions of the clip. In assembly, the pressing portion rests on the heat sink and presses the heat sink toward the CPU so that the heat sink and the CPU can have an intimate contact with each other. The engaging portions of the clip are engaged with the engaging members of the retention module. Thus, the heat sink is secured to the CPU. However, with the development of computer industry, more and more electronic components need to be arranged on the printed circuit board, which results that there is no sufficient space around the CPU to accommodate the retention module. Therefore, the locking device as mentioned above no longer can be used.
In order to overcome the problem set forth above, a locking device frugally occupying space arises to secure a heat sink to a CPU. The locking device comprises two retaining frames and four fasteners. Each retaining frame, substantially a C-shaped strip, is formed by stamping a metal plate, and has two retaining feet at two ends thereof respectively. The retaining frames are respectively fixed to two opposite sides of a base of the heat sink via several screws, and have the retaining feet extending away from the base. Then the heat sink is fixed to the printed circuit board via the fasteners engaging in fixing holes defined in the retaining feet of the retaining frames and fixing apertures defined in a fixture attached to a bottom face of the printed circuit board. However, due to the stamping process, considerable amount of scrap metal is produced for forming the retaining frames. Therefore, the cost of the retaining frames is considerably high.